This invention relates to engine analyzers and more particularly relates to apparatus for reading engine specifications into an analyzer and for storing information produced by the analyzer.
Quite recently, a vehicle engine analyzer employing a microprocessor and memory has been developed. This analyzer is described in detail in U.S. Application Ser. No. 641,362 filed in the name of Cashel et al on Dec. 16, 1975, now abandoned.
Another piece of automotive diagnostic equipment known as "Autosense" has been developed by the Hamilton Standard Division of the United Technologies. In the Autosense system, information needed to test automobiles, including specifications, is stored on a tape cassette. The tape cassette is operated in order to read electronic signals into the system. After the system is connected to a vehicle engine, it produces a printout which shows whether various vehicle engine parameters are greater than or less than the specification limits stored on the tape cassette.
Experience has shown that storage of engine specifications on a tape cassette has a number of disadvantages. The information stored on the cassette is not in visible form and, therefore, cannot be interpreted by an operator of the system. In addition, the cassettes are more bulky to store than many other record-bearing media. If specifications for more than one vehicle are stored on a single tape, it is difficult for the operator of the system to locate the proper portion of the tape which pertains to the vehicle being diagnosed.
Accordingly, it is an object of the present invention to provide a media for specifications which can be read by a human operator as well as automatic analyzing equipment.
Another object of the invention is to provide a media of the foregoing type which can be stored easily and which bears specifications for only a single type of vehicle which can be identified easily.
Still another object of the invention is to provide a system of the foregoing kind in which the machine-readable code is automatically converted into electronic digital signals which can be rapidly stored in the memory of the microprocessor.
Yet another object of the invention is to provide a media of the foregoing type on which a machine-writable code can be stored.
By using the foregoing techniques, information can be stored and read into a computerized engine analyzer with a degree of accuracy and convenience heretofore unavailable. According to a preferred aspect of the invention, the engine specifications for a single type of vehicle are carried on a sheet in two forms:
(1) Conventional printed alpha-numeric form which can be read by an operator; and
(2) Machine-readable code which can be converted automatically to digital signals storable in the memory of a microprocessor.
The use of this technique offers a number of advantages. By storing the specifications on a sheet in conventional printed alpha-numeric form, the operator can quickly identify the vehicle to be diagnosed and can read for himself the specifications. While the engine analyzer is performing automatic phases of the diagnosis, the operator can use the sheet specifications for manual engine performance checking. By storing the operator-readable and machine-readable specifications on the same sheet, the record-keeping requirements of the operator are cut in half. In addition, by limiting the specifications to one vehicle type per sheet, the operator can easily locate the machine-readable specifications which are needed for the analyzer.
According to another feature of the invention, the engine analyzer writes information pertaining to analysis on the sheet in machine-readable form. The sheet provides a convenient means of storing the information for use during subsequent analysis.